Typical electrochemical sensors measure target-induced changes in current output. Such measures of target binding are inconsistent across individual sensors, and furthermore, signal will drift over time when the sensor is deployed for long periods. These shortcomings can be avoided by the novel use of chronoamperometry to measure current decay kinetics as the indicator of target binding. Current decay lifetimes will vary in a concentration dependent manner, but remain stable across individual sensors and over time, allowing for calibration-free operation. By these methods, aptamer based electrochemical sensors and other sensor types may be deployed in vivo for extended periods of time and will provide accurate measurement of target binding without calibration.
